README
¶
Zap Core for systemd Journal
Package zapjournld provides zap Core for systemd Journal. It supports structured logging.
Applications may use zap logger to write logs directly into journald and may relatively freely define additional fields, which will be indexed by journald.
Information about common and custom journald fields is available on https://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html.
Example
package main
import (
"fmt"
"git.frostfs.info/TrueCloudLab/zapjournald"
"go.uber.org/zap"
"github.com/ssgreg/journald"
"go.uber.org/zap/zapcore"
)
func main() {
// StandardLogger
standardLogger, _ := NewStandardLogger("info")
standardLogger.Info("Simple log raw 1")
}
func NewStandardLogger(lvlStr string) (*zap.Logger, zap.AtomicLevel) {
lvl, err := getLogLevel(lvlStr)
if err != nil {
panic(err)
}
zc := zap.NewProductionConfig()
zc.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
zc.Level = zap.NewAtomicLevelAt(lvl)
// Initialize Zap.
encoder := zapcore.NewJSONEncoder(zc.EncoderConfig)
core := zapjournald.NewCore(zap.NewAtomicLevelAt(lvl), encoder, &journald.Journal{}, zapjournald.SyslogFields)
coreWithContext := core.With([]zapcore.Field{
zapjournald.SyslogFacility(zapjournald.LogDaemon),
zapjournald.SyslogIdentifier(),
zapjournald.SyslogPid(),
})
l := zap.New(coreWithContext, zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)))
return l, zc.Level
}
func getLogLevel(lvlStr string) (zapcore.Level, error) {
var lvl zapcore.Level
err := lvl.UnmarshalText([]byte(lvlStr))
if err != nil {
return lvl, fmt.Errorf("incorrect logger level configuration %s (%v), "+
"value should be one of %v", lvlStr, err, [...]zapcore.Level{
zapcore.DebugLevel,
zapcore.InfoLevel,
zapcore.WarnLevel,
zapcore.ErrorLevel,
zapcore.DPanicLevel,
zapcore.PanicLevel,
zapcore.FatalLevel,
})
}
return lvl, nil
}
Results
You can read simple view like this:
sudo journalctl -f
Apr 07 13:06:34 user ___11go_build_git_frostfs_info_TrueCloudLab_zapjournald_main[330983]: {"level":"info","ts":"2023-04-07T13:06:34.990+0300","msg":"Simple log raw 1","SYSLOG_FACILITY":3,"SYSLOG_IDENTIFIER":"___11go_build_git_frostfs_info_TrueCloudLab_zapjournald_main","SYSLOG_PID":330983}
Or you can find lines by indexed field
sudo journalctl SYSLOG_PID=76385
Apr 07 13:06:34 user ___11go_build_git_frostfs_info_TrueCloudLab_zapjournald_main[330983]: {"level":"info","ts":"2023-04-07T13:06:34.990+0300","msg":"Simple log raw 1","SYSLOG_FACILITY":3,"SYSLOG_ID>
Or you can read full-structured view like this:
sudo journalctl SYSLOG_PID=76385 --output=json-pretty
{
"PRIORITY" : "6",
"_SYSTEMD_OWNER_UID" : "1000",
"_HOSTNAME" : "user",
"__MONOTONIC_TIMESTAMP" : "153798818198",
"_SYSTEMD_SLICE" : "user-1000.slice",
"_GID" : "1000",
"_AUDIT_LOGINUID" : "1000",
"_UID" : "1000",
"SYSLOG_IDENTIFIER" : "___11go_build_git_frostfs_info_TrueCloudLab_zapjournald_main",
"__REALTIME_TIMESTAMP" : "1680861994990646",
"_CAP_EFFECTIVE" : "0",
"_COMM" : "___11go_build_g",
"_AUDIT_SESSION" : "59",
"__CURSOR" : "s=9e2d157a286a437ea3405618239c1e07;i=14a96;b=bc1bc632f462476abc9e3e3b0c517f6c;m=23cf1fb996;t=5f8bc2e20bc36;x=9c6c4a86b6da43c",
"_SYSTEMD_USER_SLICE" : "app.slice",
"_SYSTEMD_CGROUP" : "/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome-jetbrains\\x2dgoland-203587.scope",
"MESSAGE" : "{\"level\":\"info\",\"ts\":\"2023-04-07T13:06:34.990+0300\",\"msg\":\"Simple log raw 1\",\"SYSLOG_FACILITY\":3,\"SYSLOG_IDENTIFIER\":\"___11go_build_git_frostfs_info_TrueCloudLab_zapjournal>
"_SOURCE_REALTIME_TIMESTAMP" : "1680861994990539",
"_MACHINE_ID" : "82be99c92deb4b36850366d7742de698",
"SYSLOG_FACILITY" : "3",
"_BOOT_ID" : "bc1bc632f462476abc9e3e3b0c517f6c",
"_PID" : "330983",
"_SELINUX_CONTEXT" : "unconfined\n",
"_SYSTEMD_UNIT" : "user@1000.service",
"_TRANSPORT" : "journal",
"_SYSTEMD_INVOCATION_ID" : "ed23dc57a96340029ef8bf9956182c20",
"_SYSTEMD_USER_UNIT" : "app-gnome-jetbrains\\x2dgoland-203587.scope",
"SYSLOG_PID" : "330983"
}
License
Documentation
¶
Index ¶
Constants ¶
const ( SyslogFacilityField = "SYSLOG_FACILITY" SyslogIdentifierField = "SYSLOG_IDENTIFIER" SyslogPidField = "SYSLOG_PID" SyslogTimestampField = "SYSLOG_TIMESTAMP" )
Syslog compatibility fields.
const LogFacmask = 0x03f8
LogFacmask is used to extract facility part of the message.
Variables ¶
var SyslogFields = []string{ SyslogFacilityField, SyslogIdentifierField, SyslogPidField, SyslogTimestampField, }
SyslogFields contains slice of fields that are indexed by syslog by default.
Functions ¶
func NewPartialEncoder ¶
NewPartialEncoder wraps existing encoder to avoid output of some provided fields. The main use case is to ignore SyslogFields that leak into ConsoleEncoder and provide no additional info for the human.
func SyslogFacility ¶
func SyslogIdentifier ¶
Types ¶
type Core ¶
type Core struct {
zapcore.LevelEnabler
// contains filtered or unexported fields
}
Core for zapjournald.
Implements zapcore.LevelEnabler and zapcore.Core interfaces.
func (*Core) Check ¶
func (core *Core) Check(entry zapcore.Entry, checked *zapcore.CheckedEntry) *zapcore.CheckedEntry
Check determines whether the supplied Entry should be logged (using the embedded LevelEnabler and possibly some extra logic). If the entry should be logged, the Core adds itself to the CheckedEntry and returns the result.
Callers must use Check before calling Write.
Source Files